Angiogenesis In Prostate Cancer Research Articles

SRPK1 inhibition in prostate cancer: A novel anti-angiogenic treatment through modulation of VEGF alternative splicing

Prostate cancer remains one of the leading causes of cancer death in men around the world, regardless of intense research and development of novel therapies in the last 10 years. One of the new avenues that has been tested ⿿ inhibition of angiogenesis ⿿ has been disappointing so far in clinical studies in spite of strong evidence that determinants of angiogenesis (e.g. vascular endothelial growth factor) are strongly associated with disease progression. One of the reasons for these outcomes may be our poor understanding of the biology of angiogenesis in prostate cancer (and probably other cancers as well) resulting in inhibition of both detrimental and favourable molecules. We discuss here novel targeted and more specific approaches to inhibit angiogenesis in prostate cancer as well as a completely new therapeutic modality to do this ⿿ modulation of alternative splicing ⿿ that may be applicable to other molecules/biological processes as well.

전립선 암세포에서 delphinidin에 의한 HIF-1α와 STAT3 억제를 통한 혈관내피 성장 인자 발현 저해 효과

Delphinidin is a blue-red pigment and one of the major anthocyanins in plants. It plays an important role in anti-oxidant, anti-inflammatory, anti-mutagenic and anti-cancer properties. In this study, we investigated the inhibitory effects of delphinidin on vascular endothelial growth factor (VEGF) gene expression, an important factor involved in angiogenesis and tumor progression in human prostate cancer. Delphinidin decreased levels of epidermal growth factor (EGF)-induced VEGF mRNA expression in PC-3M cells. The expression of the EGF-induced hypoxia inducible factor- (HIF-) and signaling transducer and activator of transcription 3 (STAT3) proteins, which are the major transcription factors for VEGF, were inhibited by delphinidin. In addition, delphinidin decreases HRE-promoter reporter gene activity, suggesting that delphinidin can suppress the transcription of HIF- under EGF induction, leading to a decrease in the expression of VEGF. Delphinidin specifically suppressed the phosphorylation of Akt, p70S6K, and 4EBP1, but not the phosphorylation of EGFR. Therefore, our results suggest that delphinidin may inhibit human prostate cancer progression and angiogenesis by inhibiting HIF-, STAT3 and VEGF gene expression.

Quercetin inhibits angiogenesis through thrombospondin-1 upregulation to antagonize human prostate cancer PC-3 cell growth in vitro and in vivo

The rapid growth, morbidity and mortality of prostate cancer, and the lack of effective treatment have attracted great interests of researchers to find novel cancer therapies aiming to inhibit angiogenesis and tumor growth. Quercetin is a flavonoid compound that widely exists in the nature. Our previous study preliminarily demonstrated that quercetin effectively inhibited human prostate cancer cell xenograft tumor growth by inhibiting angiogenesis. Thrombospondin-1 (TSP-1) is the first reported endogenous anti-angiogenic factor that can inhibit angiogenesis and tumorigenesis. However, the relationship between quercetin inhibiting angiogenesis and TSP-1 upregulation in prostate cancer has not been determined. Thus, we explored the important role of TSP-1 upregulation in reducing angiogenesis and anti-prostate cancer effect of quercetin both in vitro and in vivo for the first time. After the selected doses were used for a certain time, quercetin i) significantly inhibited PC-3 and human umbilical vein endothelial cells (HUVECs) proliferation, migration and invasion in a dose-dependent manner; ⅱ) effectively inhibited prostate cancer PC-3 cell xenograft tumor growth by 37.5% with 75 mg/kg as compared to vehicle control group, more effective than 25 (22.85%) and 50 mg/kg (29.6%); ⅲ) was well tolerated by BALB/c mice and no obvious toxic reactions were observed; ⅳ) greatly reduced angiogenesis and led to higher TSP-1 protein and mRNA expression both in vitro and in vivo in a dose-dependent manner. Therefore, quercetin could increase TSP-1 expression to inhibit angiogenesis resulting in antagonizing prostate cancer PC-3 cell and xenograft tumor growth. The present study can lay a good basis for the subsequent concrete mechanism study and raise the possibility of applying quercetin to clinical for human prostate cancer in the near future.

Abstract B28: Tumor-associated macrophages and angiogenesis in prostate cancer

Abstract Introduction: Role of tumor associated macrophages (TAM) and angiogenesis is being extensively evaluated. Macrophages are subdivided in two phenotypes: M1 (classically activated: promote inflammation, act against cancer growth) and M2 (alternatively activated: promote healing, angiogenesis; could support tumor growth). Our preliminary study was intended to study number of macrophages (CD68 positive), M2 macrophages (CD163 positive) and microvessels (ERG positive) between non-neoplastic and neoplastic prostate tissue. Methods: We evaluated 10 radical prostatectomy specimens (RP) with prostate cancer (PCA) (cases) and 10 cystoprostatectomy specimens (CP) negative for PCA (controls). Representative paraffin blocks were selected for analysis and stained by immunohistochemistry for CD68 PGM1, CD163 and ERG. For RP specimens, two distinct blocks were selected: one with tumor (RP-T) and one away from tumor (RP-NT). Macrophages count was done using two methods. Method 1: average manual count in 12 fields at 400X magnification in areas uninvolved by chronic inflammation (CI), away from hotspots. Method 2: average count in three hotspots (associated with CI) at 400X magnification with manual assistance on Aperio Image Spectrum Software. Vessels count was done using a Chalkley point counting technique at 100X magnification. Statistical analysis was done using t test and Pearson correlation. Results: Different degree of CI was found in most CP and RP samples, ranging from focal mild to multifocal severe (hotspots). Mean age of CP and RP patients was 58 and 60 years, respectively. RP Gleason score ranged from 6 to 9. No significant difference in CD68, CD163 and ERG positive cells existed between the three groups by t-test. The CD68 count in RP-T was 104 by method 1 and 114 by method 2. The CD163 count in RP-T was 51 by method 1 and 54 by method 2. ERG count in RP-T was 6.9. A positive correlation of M2 macrophages (method 2) with microvessels in RP-T (p=0.046) was found. None of the counts correlated with Gleason score. Conclusions: Our preliminary study found no significant difference in TAM between non-neoplastic and neoplastic prostate tissue, independently from the association with CI. The vessel count in prostate tumor positively correlated with M2 macrophages, suggesting a possible crosstalk between M2 macrophages and tumor cells promoting angiogenesis. These findings require further validation in additional studies including a larger sample size. Citation Format: Pallavi Patil, Paula Carver, Karen Streator Smith, Jeffrey Lin, Cristina Magi-Galluzzi. Tumor-associated macrophages and angiogenesis in prostate cancer. [abstract]. In: Proceedings of the AACR Special Conference: Tumor Angiogenesis and Vascular Normalization: Bench to Bedside to Biomarkers; Mar 5-8, 2015; Orlando, FL. Philadelphia (PA): AACR; Mol Cancer Ther 2015;14(12 Suppl):Abstract nr B28.

Targeting the angiogenic 'splice' switch; inhibition of SRPK1 as a novel therapeutic approach in prostate cancer

Pathological angiogenesis occurs when the balance between pro-angiogenic and anti-angiogenic factors is tipped enabling an angiogenic switch. VEGF-A is the primary inducer of angiogenesis but is alternatively spliced at the pre-mRNA level to produce pro-angiogenic and anti-angiogenic isoforms. In previous work we showed that the balance of VEGF-A isoforms is regulated by SRSF1, which is regulated by phosphorylation from SRPK1 in renal epithelial cells, colon cancer cells, retinal epithelial cells and melanoma cells. SRPK1 and SRSF1 promote expression of pro-angiogenic VEGF-A 165 a and knockdown or inhibition of SRPK1 switches this balance towards anti-angiogenic VEGF-A 165 b, which inhibits angiogenesis and tumor growth in colon cancer and melanoma cells. In our recent study, Mavrou et al ., 2014, we report that SRPK1 expression is upregulated in both prostatic intraepithelial neoplasia and malignant tissue sections from patients with radical prostatectomy. Knockdown or inhibition of SRPK1 with small molecule inhibitors leads to a splicing switch towards anti-angiogenic VEGF-A in PC-3 cells, a reduction in angiogenesis and inhibition of tumor growth in xenograft models. Specifically inhibiting pro-angiogenic VEGF-A splice isoforms through targeted inhibition of the splicing kinase SRPK1 is a novel approach which could enable development of therapies that are safer and more efficacious than current drugs. This study provides proof-of-concept for modulation of SRPK1 to normalise the endogenous VEGF-A splicing balance, enabling inhibition of angiogenesis and tumor growth in prostate cancer. Here, we discuss our recent findings and ongoing work to develop these findings into a novel therapeutic approach.

Dysregulation of the vascular endothelial growth factor and semaphorin ligand-receptor families in prostate cancer metastasis.

BackgroundThe vascular endothelial growth factor (VEGF) family is central to cancer angiogenesis. However, targeting VEGF as an anti-cancer therapeutic approach has shown success for some tumor types but not others. Here we examine the expression of the expanded VEGF family in prostate cancer, including the Semaphorin (Sema) family members that compete with VEGFs for Neuropilin binding and can themselves have pro- or anti-angiogenic activity.ResultsFirst, we used multivariate statistical methods, including partial least squares and clustering, to examine VEGF/Sema gene expression variability in previously published prostate cancer microarray datasets. We show that unlike some cancers, such as kidney cancer, primary prostate cancer is characterized by both a down-regulation of the pro-angiogenic members of the VEGF family and a down-regulation of anti-angiogenic members of the Sema family. We found pro-lymphangiogenic signatures, including the genes encoding VEGFC and VEGFD, associated with primary tumors that ultimately became aggressive. In contrast to primary prostate tumors, prostate cancer metastases showed increased expression of key pro-angiogenic VEGF family members and further repression of anti-angiogenic class III Sema family members. Given the lack of success of VEGF-targeting molecules so far in prostate cancer, this suggests that the reduction in anti-angiogenic Sema signaling may potentiate VEGF signaling and even promote resistance to VEGF-targeting therapies. Inhibition of the VEGF ‘accelerator’ may need to be accompanied by promotion of the Sema ‘brake’ to block cancer angiogenesis. To leverage our mechanistic understanding, and to link multigene expression changes to outcomes, we performed individualized computational simulations of competitive VEGF and Sema receptor binding across many tumor samples. The simulations suggest that loss of Sema expression promotes angiogenesis by lowering plexin signaling, not by potentiating VEGF signaling via relaxation of competition.ConclusionsThe combined analysis of bioinformatic data with computational modeling of ligand-receptor interactions demonstrated that enhancement of angiogenesis in prostate cancer metastases may occur through two different routes: elevation of VEGFA and reduction of class 3 Semaphorins. Therapeutic inhibition of angiogenesis in metastatic prostate cancer should account for both of these routes.Electronic supplementary materialThe online version of this article (doi:10.1186/s12918-015-0201-z) contains supplementary material, which is available to authorized users.

Genetic interaction of P2X7 receptor and VEGFR-2 polymorphisms identifies a favorable prognostic profile in prostate cancer patients.

VEGFR-2 and P2X7 receptor (P2X7R) have been described to stimulate the angiogenesis and inflammatory processes of prostate cancer. The present study has been performed to investigate the genetic interactions among VEGFR-2 and P2X7R SNPs and their correlation with overall survival (OS) in a population of metastatic prostate cancer patients. Analyses were performed on germline DNA obtained from blood samples and SNPs were investigated by real-time PCR technique. The survival dimensionality reduction (SDR) methodology was applied to investigate the genetic interaction between SNPs. One hundred patients were enrolled. The SDR software provided two genetic interaction profiles consisting of the combination between specific VEGFR-2 (rs2071559, rs11133360) and P2X7R (rs3751143, rs208294) genotypes. The median OS was 126 months (95% CI, 115.94-152.96) and 65.65 months (95% CI, 52.95-76.53) for the favorable and the unfavorable genetic profile, respectively (p < 0.0001). The genetic statistical interaction between VEGFR-2 (rs2071559, rs11133360) and P2X7R (rs3751143, rs208294) genotypes may identify a population of prostate cancer patients with a better prognosis.

Abstract 1386: KLF5 inhibits angiogenesis in PTEN-deficient prostate cancer by attenuating AKT activation and subsequent HIF1α accumulation

Abstract Background: KLF5 is a basic transcriptional factor that regulates multiple physiopathological processes. Our recent study showed that deletion of Klf5 in mouse prostates promotes tumorigenesis initiated by the deletion of Pten. While molecular characterization of Klf5-null tumors suggested that angiogenesis was partially responsible for tumor promotion, the precise function and mechanism of KLF5 deletion in prostate tumor angiogenesis remain unclear. Results: Using histological staining of Pten-null mouse prostates, we observed that deletion of Klf5 significantly increased the number of microvessels, which was accompanied by the upregulation of multiple angiogenesis-related genes based on microarray analysis with MetaCore software. In human umbilical vein endothelial cells (HuVECs), tube formation and migration, both of which are indicators of angiogenic activities, were decreased by conditioned media from PC-3 and DU 145 human prostate cancer cells with KLF5 overexpression, but increased by media from cells with KLF5 knockdown. HIF1α, a key angiogenesis inducer, was upregulated by KLF5 loss at the protein but not the mRNA level in both mouse tissues and human cell lines, as examined by immunohistochemical staining, real-time RT-PCR and Western blotting. Consistently, KLF5 loss also upregulated VEGF and PDGF, two pro-angiogenic mediators of HIF1α function, as analyzed by immunohistochemical staining in mouse tissues and ELISA in conditioned media. Mechanistically, AKT activity, which caused the accumulation of HIF1α, was increased by KLF5 knockout or knockdown but decreased by KLF5 overexpression. Consistently, PI3K/AKT inhibitors abolished the effects of KLF5 knockdown on angiogenic activity, HIF1α accumulation, and VEGF and PDGF expression. Conclusion: KLF5 loss enhances tumor angiogenesis by attenuating PI3K/AKT signaling and subsequent accumulation of HIF1α in PTEN deficient prostate tumors. Citation Format: Xinpei Ci, Changsheng Xing, Baotong Zhang, Zhiqian Zhang, Jenny Jianping Ni, Wei Zhou, Jin-Tang Dong. KLF5 inhibits angiogenesis in PTEN-deficient prostate cancer by attenuating AKT activation and subsequent HIF1α accumulation. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 1386. doi:10.1158/1538-7445.AM2015-1386

Abstract 3359: PEDF modulatory action on macrophages: A new way to curb prostate cancer development

Abstract Macrophages have been described as one of the main inflammatory components involved in prostate cancer (PCa) initiation, progression, and metastasis. PEDF (Pigment Epithelium-Derived Factor) is an anti-angiogenic factor with differentiation activities and was recently suggested as an immune-modulating factor. PEDF expression has been shown to be down-regulated in PCa compared to normal tissues. In previous studies we have demonstrated that PEDF re-expression in PCa cells curbs tumor growth in vivo and significantly prolongs the survival of tumor-bearing mice. Others have shown that PEDF expression increased the recruitment of tumor-cytotoxic macrophages into orthotopic MatLyLu rat prostate tumors suggesting a link between PEDF and inflammation in PCa. While PEDF's role in inflammation has been suggested, the precise modes of action of PEDF on macrophages still remain unknown and necessitate further investigation. Our preliminary data have showed that PEDF stimulates the migration of monocytes/macrophages using in vitro chemotaxis boyden chamber assay and towards tumor 3D spheroids. We showed that PEDF expression levels positively correlate with macrophage density in human prostate. In both cell lines and prostate specimens, we have demonstrated that PEDF directly induces the polarization of macrophages and bone marrow derived macrophages (BMDMs) towards a M1/tumor-cytotoxic pathway. As a result of their differentiation, we have found that PEDF stimulates the phagocytosis of tumor cells, which suggest another mechanism by which PCa growth is halted. We are currently investigating the molecular mechanisms by which PEDF induces migration, differentiation and phagocytic activity in macrophages. PEDF mechanisms are being investigated by expression levels of PEDF receptors (ATP5B, PNPLA2, LRP6) in macrophage cell lines and BMDMs. So far we have been identified ATP5B and PNPLA2 as the two main receptors expressed in both cell types. While all three receptors in cell lines increased, only ATP5B and PNPLA2 receptors increased in BMDMs in response to PEDF. To map the functional region involved in PEDF's inflammatory action, we are investigating the PEDF-derivative synthetic 18-mer peptide (residues 39-57). P18 has been shown to block endothelial cell chemotaxis and induces apoptosis in vitro, and to be more effective than its parental 34-mer peptide (residues 24-57) in blocking growth and angiogenesis in PCa. We were able to demonstrate that macrophages treated with P18 in comparison to PEDF, show a higher efficacy for macrophages differentiation. Using confocal microscopy we demonstrated a larger rate of phagocytosis of PCa cells by macrophages than compared to PEDF. The results of our study are of importance as they suggest that macrophages may play a key role in PEDF anti-tumor effects. A better understanding of PEDF may lead to further development of PEDF-based anticancer therapy or improvement of alternatives to chemotherapy for PCa. Citation Format: Dalia Martinez-Marin, Thomas Nelius, Olga Volpert, Stephanie Filleur. PEDF modulatory action on macrophages: A new way to curb prostate cancer development. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 3359. doi:10.1158/1538-7445.AM2015-3359

Abstract 2056: SIRT1 silencing suppresses prostate cancer growth and metastasis in an orthotopic prostate cancer mouse model

Abstract Tumor environment is critical for tumor growth and progression, and orthotopic mouse model allows accurately study tumor development in an appropriate tumor environment. SIRT1, a class III histone deacetylase, has been shown overexpressed in prostate cancer and is a biomarker for prostate cancer recurrence. Although these data have suggested the importance of the role SIRT1 plays in prostate cancer progression, the role of SIRT1 in tumor growth and progression within, specifically, a prostate tumor environment has not been established. In this study, we established an advanced prostate cancer PC3MM2 orthotopic mouse model to study the effects of SIRT1 silencing on prostate cancer growth and progression. Our data has shown that SIRT1 knockdown greatly suppresses tumor formation within a prostate tumor environment, along with an inhibition of metastasis to bone and liver. To further study the mechanism by which SIRT1 controls tumor growth and progression, we demonstrated that SIRT1 silencing reduces prostate cancer cell adhesion to cell matrix, and that this silencing also suppresses cancer cell growth and colony formation in a cell matrix dependent manner. Moreover, our data showed that SIRT1 regulates integrin expression and focal adhesion complex formation. Furthermore, we shows that SIRT1 silencing from prostate cancer cell significantly inhibited human umbilical vein endothelial cell (HUVEC) tube formation, suggests an important role of SIRT1 in prostate cancer angiogenesis. Thus, we have reported for the first time that SIRT1 plays a critical role in prostate cancer growth and progression using orthotopic mouse model, and demonstrated for the first time that SIRT1 regulates integrin expression, focal adhesion formation, tumor cell and matrix interaction, and angiogenesis. These results suggest SIRT1 regulates prostate cancer growth and progression through multiple mechanisms and that SIRT1 is a potential target in prostate cancer treatment. Citation Format: Yan Dai, Lijia Zhu, Elizabeth Cho, Audrey Hagiwara, Douglas Faller, Sun-Jin Kim, Isaiah J. Fidler, Marina Amaro. SIRT1 silencing suppresses prostate cancer growth and metastasis in an orthotopic prostate cancer mouse model. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 2056. doi:10.1158/1538-7445.AM2015-2056

Reconsideration of the clinical and histopathological significance of angiogenesis in prostate cancer: Usefulness and limitations of microvessel density measurement.

Angiogenesis plays important roles in tumor growth and cancer cell dissemination in almost all cancers. In prostate cancer, there is general agreement that increased angiogenesis is an important factor in determining tumor development and prognosis in these patients. Microvessel density is recognized as a useful marker for evaluating the angiogenic status of cancer tissues. Many investigators have reported that microvessel density is significantly associated with pathological features and outcomes in prostate cancer patients; however, some researchers have expressed opposing opinions. As the reason for such discrepancy, previous reports have suggested differences in the methodologies of measuring microvessel density in cancer tissues. In the present review, we focus on the variation in such methods, including the selected area and the method used for (semi)quantification. In particular, we discuss the relationship between malignancy potential, tumor progression, and survival and differences in the antibodies used for detection of endothelial cells in detail. We briefly compare the pathological significance and prognostic roles of microvessel density measured using von Willebrand factor, CD31, CD34, and CD105. Based on these analyses, the advantages and limitations of microvessel density measurements in prostate cancer tissues are clarified. Improved "real" and "specific" markers of cancer-related angiogenesis are necessary for better predictions of prognoses and for discussion of treatment strategies for patients with prostate cancer. However, establishment of a satisfactory cancer-related endothelial marker could take a long time. Therefore, knowledge regarding the pathological significance of microvessel density - based on understanding of the advantages and limitations of microvessel density determination methods - is important.

KLF5 inhibits angiogenesis in PTEN-deficient prostate cancer by attenuating AKT activation and subsequent HIF1α accumulation.

BackgroundKLF5 is a basic transcriptional factor that regulates multiple physiopathological processes. Our recent study showed that deletion of Klf5 in mouse prostate promotes tumorigenesis initiated by the deletion of Pten. While molecular characterization of Klf5-null tumors suggested that angiogenesis was partially responsible for tumor promotion, the precise function and mechanism of KLF5 deletion in prostate tumor angiogenesis remain unclear.ResultsApplying histological staining to Pten-null mouse prostates, we observed that deletion of Klf5 significantly increased the number of microvessels, accompanied by the upregulation of multiple angiogenesis-related genes based on microarray analysis with MetaCore software. In human umbilical vein endothelial cells (HuVECs), tube formation and migration, both of which are indicators of angiogenic activities, were decreased by conditioned media from PC-3 and DU 145 human prostate cancer cells with KLF5 overexpression, but increased by media from cells with KLF5 knockdown. HIF1α, a key angiogenesis inducer, was upregulated by KLF5 loss at the protein but not the mRNA level in both mouse tissues and human cell lines, as determined by immunohistochemical staining, real-time RT-PCR and Western blotting. Consistently, KLF5 loss also upregulated VEGF and PDGF, two pro-angiogenic mediators of HIF1α function, as analyzed by immunohistochemical staining in mouse tissues and ELISA in conditioned media. Mechanistically, AKT activity, which caused the accumulation of HIF1α, was increased by KLF5 knockout or knockdown but decreased by KLF5 overexpression. PI3K/AKT inhibitors consistently abolished the effects of KLF5 knockdown on angiogenic activity, HIF1α accumulation, and VEGF and PDGF expression.ConclusionKLF5 loss enhances tumor angiogenesis by attenuating PI3K/AKT signaling and subsequent accumulation of HIF1α in PTEN deficient prostate tumors.Electronic supplementary materialThe online version of this article (doi:10.1186/s12943-015-0365-6) contains supplementary material, which is available to authorized users.

A high-fat diet containing lard accelerates prostate cancer progression and reduces survival rate in mice: possible contribution of adipose tissue-derived cytokines.

To examine the effects of high-fat diet (HFD) containing lard on prostate cancer development and progression and its underlying mechanisms, transgenic adenocarcinoma mouse prostate (TRAMP) and TRAMP-C2 allograft models, as well as in vitro culture models, were employed. In TRAMP mice, HFD feeding increased the incidence of poorly differentiated carcinoma and decreased that of prostatic intraepithelial neoplasia in the dorsolateral lobes of the prostate, which was accompanied by increased expression of proteins associated with proliferation and angiogenesis. HFD feeding also led to increased metastasis and decreased survival rate in TRAMP mice. In the allograft model, HFD increased solid tumor growth, the expression of proteins related to proliferation/angiogenesis, the number of lipid vacuoles in tumor tissues, and levels of several cytokines in serum and adipose tissue. In vitro results revealed that adipose tissue-conditioned media from HFD-fed mice stimulated the proliferation and migration of prostate cancer cells and angiogenesis compared to those from control-diet-fed mice. These results indicate that the increase of adipose tissue-derived soluble factors by HFD feeding plays a role in the growth and metastasis of prostate cancer via endocrine and paracrine mechanisms. These results provide evidence that a HFD containing lard increases prostate cancer development and progression, thereby reducing the survival rate.

Sulfoquinovosylacylpropanediol is a novel potent radiosensitizer in prostate cancer.

To examine the effects of combined treatment with sulfoquinovosylacylpropanediol and X-ray irradiation on the remodeling of the prostate cancer microenvironment, including angiogenic and hypoxic characteristics. Human prostate cancer cells (DU145 and PC3) were implanted subcutaneously into the right hind legs of athymic nude mice. After the tumor volume reached 100-300mm(3) , 2mg/kg/day sulfoquinovosylacylpropanediol was given intravenously from day0 to day4, and cells were exposed to 4Gy X-ray irradiation on days0 and 3 (for a total of 8Gy). Tumors were fixed and stained for pathological analyses and immunohistochemical evaluations. To analyze vascular normalization, 60mg/kg pimonidazole dissolved in saline was injected intraperitoneally. Combined treatment with sulfoquinovosylacylpropanediol plus X-ray irradiation enhanced growth inhibition in DU145 xenografts. The tumor vessel density in DU145 cells significantly decreased after the combined treatment. Staining for αsmooth muscle actin in vessels was significantly increased. Pimonidazole staining, showing hypoxic lesions, was negative from 72h, but positive at 6 and 24h after the first combined treatment. In contrast, no enhancement of the microenvironment in PC3 xenografts was observed with sulfoquinovosylacylpropanediol plus X-ray irradiation. Sulfoquinovosylacylpropanediol could be a novel potent radiosensitizing agent targeting angiogenesis in prostate cancer.

Two-dimensional neovascular complexity is significantly higher in nontumor prostate tissue than in low-risk prostate cancer.

PurposeProstate cancer is the most frequent cancer in men in Europe. A major focus in urology is the identification of new biomarkers with improved accuracy in patients with low-risk prostate cancer. Here, we evaluated two-dimensional neovascular complexity in prostate tumor and nontumor biopsy cores by use of a computer-aided image analysis system and assessed the correlations between the results and selected clinical and pathological parameters of prostate carcinoma.Materials and MethodsA total of 280 prostate biopsy sections from a homogeneous series of 70 patients with low-risk prostate cancer (Gleason score 3+3, prostate-specific antigen [PSA]<10 ng/mL, and clinical stage T1c) who underwent systematic biopsy sampling and subsequent radical prostatectomy were analyzed. For each biopsy, 2-µm sections were treated with CD34 antibodies and were digitized by using an image analysis system that automatically estimates the surface fractal dimension.ResultsOur results showed that biopsy sections without cancer were significantly more vascularized than were tumors. No correlations were found between the vascular surface fractal dimension and patient's age, PSA and free-to-total PSA ratios, pathological stage, Gleason score, tumor volume, vascular invasion, capsular penetration, surgical margins, and biochemical recurrence.ConclusionsThe value of angiogenesis in prostate cancer is still controversial. Our findings suggest that low-risk prostate cancer tissues are less vascularized than are nontumor tissues. Further studies are necessary to understand whether angiogenesis is a hallmark of intermediate- and high-risk prostate cancer.

SPAG9 expression is increased in human prostate cancer and promotes cell motility, invasion and angiogenesis in vitro.

Sperm-associated antigen 9 (SPAG9) is a recently characterized oncoprotein involved in the progression of several human malignancies. To elucidate the role of SPAG9 in the development of human prostate cancer (PCa), tissue microarray (TMA) and immunohistochemistry were used to detect the clinical relevance of SPAG9 in PCa tissues. We found that SPAG9 expression was increased in the PCa tissues when compared with the level in the tumor adjacent normal prostate tissues, and increased SPAG9 staining was significantly correlated with TNM stage and tumor grade. We also examined prostate cancer cell motility, invasion and angiogenesis ability following reduced SPAG9 expression by siRNA. Our data showed that knockdown of SPAG9 in prostate cancer cell lines inhibited cell motility and invasion due to the inactivation of metalloproteinase-2 (MMP‑2)/MMP-9 by upregulation of tissue inhibitor of metalloproteinase-1 (TIMP-1)/TIMP-2. Furthermore, downregulation of vascular endothelial growth factor (VEGF) secretion greatly contributed to the reduced ability of angiogenesis. Our data indicate that SPAG9 expression is significantly increased in PCa and it may be involved in the process of prostate cancer cell motility, migration and angiogenesis.

P1-5-2 - Bradykinin Promotes Vascular Endothelial Growth Factor-Dependent Angiogenesis in Human Prostate Cancer

Background: Prostate cancer is the most commonly diagnosed malignancy in men and shows a tendency for metastasis to distant organs. Angiogenesis is required for metastasis. Bradykinin (BK) is an inflammatory mediator involved in tumor growth and metastasis, but its role in vascular endothelial growth factor (VEGF) expression and angiogenesis in human prostate cancer remains unknown. The aim of this study was to examine whether BK promotes prostate cancer angiogenesis via VEGF expression.Methods: We knocked down bradykinin expression in human prostate cancer cells and assessed their capacity to control VEGF expression and angiogenesis. Signal transduction of bradykinin-mediated VEGF expression was evaluated by qPCR, ELISA, Western blot, and luciferace assay.Results: We found that exogenous bradykinin increased VEGF expression in prostate cancer cells and further promoted tube formation in endothelial progenitor cells and human umbilical vein endothelial cells. Pretreatment of prostate cancer with B2 receptor antagonist or small interfering RNA (siRNA) reduced bradykinin-mediated VEGF production. The Akt and mammalian target of rapamycin (mTOR) pathways were activated after bradykinin treatment, and bradykinin-induced VEGF expression was abolished by the specific inhibitor and siRNA of the Akt and mTOR cascades. bradykinin also promoted nuclear factor-kB (NF-kB) and activator protein 1 (AP-1) activity. Importantly, bradykinin knockdown reduced VEGF expression and abolished prostate cancer cell conditional medium-mediated angiogenesis.Conclusions: Our results demonstrate that bradykinin operates through the B2 receptor, Akt, and mTOR, which in turn activate NF-kB and AP-1, activating VEGF expression and contributing to angiogenesis in human prostate cancer.

The future perspectives in transrectal prostate ultrasound guided biopsy.

Prostate cancer is one of the most common neoplasms in men. Transrectal ultrasound (TRUS)-guided systematic biopsy has a crucial role in the diagnosis of prostate cancer. However, it shows limited value with gray-scale ultrasound alone because only a small number of malignancies are visible on TRUS. Recently, new emerging technologies in TRUS-guided prostate biopsy were introduced and showed high potential in the diagnosis of prostate cancer. High echogenicity of ultrasound contrast agent reflect the increased status of angiogenesis in tumor. Molecular imaging for targeting specific biomarker can be also used using ultrasound contrast agent for detecting angiogenesis or surface biomarker of prostate cancer. The combination of TRUS-guided prostate biopsy and ultrasound contrast agents can increase the accuracy of prostate cancer diagnosis. Elastography is an emerging ultrasound technique that can provide the information regarding tissue elasticity and stiffness. Tumors are usually stiffer than the surrounding soft tissue. In two types of elastography techniques, shearwave elastography has many potential in that it can provide quantitative information on tissue elasticity. Multiparametric magnetic resonance imaging (MRI) from high resolution morphologic and functional magnetic resonance (MR) technique enables to detect more prostate cancers. The combination of functional techniques including apparent diffusion coefficient map from diffusion weighted imaging, dynamic contrast enhanced MR and MR spectroscopy are helpful in the localization of the prostate cancer. MR-ultrasound (US) fusion image can enhance the advantages of both two modalities. With MR-US fusion image, targeted biopsy of suspicious areas on MRI is possible and fusion image guided biopsy can provide improved detection rate. In conclusion, with recent advances in multiparametric-MRI, and introduction of new US techniques such as contrast-enhanced US and elastography, TRUS-guided biopsy may evolve toward targeted biopsies rather than systematic biopsy for getting information reflecting the exact status of the prostate.

Fasudil inhibits prostate cancer-induced angiogenesis in vitro.

Inhibition of angiogenesis is an important therapeutic strategy for advanced stage prostate cancer (PCa). RhoA/Rho-associated protein kinases (ROCK) are key regulators of the cytoskeleton and have been implicated in PCa angiogenesis. We investigated the anti-angiogenic effects of fasudil, a ROCK inhibitor, on PCa-induced angiogenesis in vitro. Proliferation of PCa-conditioned human umbilical vein endothelial cells (HUVECs) was assessed using a bromodeoxyuridine (BrdU) assay, and migration was assessed with a wound healing assay. In vitro angiogenesis of PCa-conditioned HUVECs was evaluated by tube formation and a spheroid sprouting assay. Fasudil inhibited PCa-induced endothelial cell proliferation at a concentration of 100 µM, and also decreased PCa-induced endothelial cell migration at a concentration of 30 µM. In the in vitro angiogenesis assay, fasudil exerted a more significant effect. Tube formation was significantly inhibited at fasudil concentrations exceeding 3 µM, and spheroid sprouts were significantly thinner and shorter (at fasudil concentrations of 10 and 30 µM, respectively). Western blotting results showed that expression of phosphorylated myosin phosphatase target subunit 1 (MYPT-1) was significantly lower after fasudil treatment, confirming that fasudil inhibited ROCK activity in these model systems. These data suggest that fasudil may be a useful anti-angiogenic agent for PCa.

Prostate cancer and new insights in angiogenesis.

Prostate cancer and new insights in angiogenesis.